You'll need to get at LEAST
TWO sugar gliders - one will wither on you...
They're a very social animal ~ unlike a parrot, rabbit, etc. which do fine alone (most prefer solitude), sugar gliders must have at least one fellow sugar glider around.
Now, something like a pet tarantula
must be a lone pet - otherwise you end up with just one fat tarantula (yep, they are cannibals)